1. Field of the Invention
The invention relates to an image processing apparatus and an image processing method. More particularly, the invention relates to an image processing apparatus for adjusting a gray level of a pixel block of a display apparatus and an image processing method for adjusting a gray level of a pixel block of a display apparatus.
2. Description of Related Art
The three-dimensional (3D) display technique is the mainstream in this digital display era. When the 3D display technique is applied to the entertainment field, the field of medical research, or other fields, users are allowed to feel as if they were present. In terms of entertainment, when users watch 3D movies or play 3D videogames, the 3D display technique may create the visual effect on an object as to fly toward the users and pop out from the screen, so as to give the users the feeling of being there. As such, the 3D display technique indeed leads to development of movie and gaming industry.
At present, the 3D display technique may be roughly categorized into two types. One is the stereoscopic type which requires a viewer to wear specially designed glasses, and the other is the auto-stereoscopic type which allows the viewer to watch images or videos directly with naked eyes. According to the operational principle of an auto-stereoscopic display apparatus, a fixed barrier is utilized to control images received by left and right eyes of the viewer. However, according to visual characteristics of human eyes, when two images with the same content but different parallax are respectively captured by a viewer's left and right eyes, two images that seem to be overlapped may be interpreted as a 3D image. Besides, according to the operational principle of a stereoscopic stereo display apparatus, the display apparatus displays left-eye and right-eye images that can be respectively sent to the left and right eyes of the viewer who wears glasses, so as to generate a 3D image.
In the conventional dither algorithm for a 6-bit source driver controlling a thin film transistor liquid crystal display (TFT-LCD) panel, an 8-bit to 6-bit resolution dither function is provided. Particularly, the dither function applies a concept of averages to accomplish a four-time resolution refinement of an image. For instance, the dither function manages to mimic 256 colors (supposed to be synthesized to 8 bits of memory) with only 6 bits of memory. Besides, a 4×4 pixel block for four frames is arranged in a normal dither matrix. Please refer to FIG. 1A schematically illustrating arrangement of a dither matrix in a two-dimensional (2D) display. As shown in FIG. 1A, such arrangement of the dither matrix is sufficiently applicable to the 2D display and allows the 2D display to display images with high quality.
Nonetheless, when the conventional arrangement of the dither matrix applicable to the 2D display is applied to a 3D display, image flickers or apparent patterns occur. In an exemplary polarizing 3D display technique, pixels of a 3D display in odd rows and even rows separately present a left-eye image and a right-eye image, and a pair of polarizing glasses allows the left and right eyes to respectively receive the corresponding images. Thereby, the arrangements of the dither matrix respectively corresponding to the left-eye image and the right-eye image are shown in FIG. 1B. Namely, FIG. 1B schematically illustrates the conventional arrangements of a dither matrix respectively corresponding to the left and right eyes even when a 3D display mode is activated. It can be observed from FIG. 1B that the arrangements of a dither matrix corresponding to the left and right eyes differ from each other, thus resulting in image flickers or apparent patterns and significantly reducing the 3D image quality.